FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

IGNORE THE HEADLINES: CALCIUM CHANNEL BLOCKERS SAFE

Question: I have high blood pressure for which my doctor has given me a calcium channel blocker. I'm concerned because of the recent news reports saying these medications are dangerous. I also don't want to make my doctor angry at me by questioning his judgment, so I'm writing you. Are calcium channel blockers safe to take?

Answer: The short answer is that calcium channel blockers are safe for the treatment of high blood pressure and for other problems such as angina pectoris, heart rhythm abnormalities, migraine headaches and Raynaud's phenomenon. But, I think a bit more information will help you understand why I say this.

Calcium channel blockers decrease the rate at which charged atoms of calcium called ions are transported from the blood to the inside of muscle tissue, a process that is necessary for the muscle to become ready to contract. Calcium channel blockers actually interfere with some of the "doorways" through which the calcium must pass to get into the cell. A result of this decrease of calcium in the muscle tissue is that the vigor of heart muscle contractions lessens. Similarly, the muscles inside the arteries are more relaxed and wide open rather than restricted and narrow. These effects are desirable for those with high blood pressure, angina pectoris, and other heart and circulatory problems.

All the commotion about calcium channel blockers started when an epidemiologist, Bruce Psaty, M.D., from the University of Washington in Seattle, spoke with an Associated Press reporter about his review of medical records of a few thousand individuals at one health maintenance organization (HMO). His study attempted to determine if the calcium channel blockers nifedipine, diltiazem or verapamil, when used to lower blood pressure, made a difference in the occurrence of heart attack, a known complication of high blood pressure. He selected the records of individuals who were taking one of these blood pressure medications and divided them into two groups 623 who had a heart attack between 1986 and 1993, and 2032 who had not. From his results, he concluded that taking these medications causes an increased risk of heart attack.

There are technical weaknesses in this type of "after-the-fact" study that make such findings questionable. It does, however, raise questions that will help other researchers design much more valid experimental studies. These investigations may eventually help us figure out if any "cause and effect" relationship is really involved here and, if so, which segments of our society, in terms of such factors as age, race, ethnicity and gender, are likely to be most affected.

I'm deeply concerned about the sensational way this study was presented to the public before the scientific community who has the background to accurately interpret the findings had a chance to put the results in proper perspective. The average person, like you, is alarmed by such inaccurate medical journalism. As an example, the lead paragraph of the article in my local paper started with "Six million Americans may be increasing their risk of heart attacks by 60 percent by taking a class of drugs to lower blood pressure, researchers say." It would surely scare me if I was taking a calcium channel blocker!

Here's the bottom line: Calcium channel blockers have been used for years to treat conditions of the circulatory system. The risks from their use are minimal. The potential benefits are high. The only question this new research raises is whether or not other blood pressure treatments lower the risk of a first heart attack better than calcium channel blockers. It will take more research to clarify this issue. And while we all wait for this research, please talk to your doctor. Answering your questions and supplying expert advice, after all, is what you pay us to do.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.